The Australian said the Grove built FW27 car is still not fast enough.
"We are working on it," he said on Wednesday. "It's no good dreaming -- we need more grip, more power, more downforce."
Asked how distant that elusive maiden grand prix win is, the 28-year-old replied: "We're a way off yet -- but you can still enjoy your (racing)."
Mark said: "It's great to have street circuits and it's a shame we don't have more of them."
A few grands prix in the famous Principality, however, have been held on this very date -- the nineteenth day of May.
In 1957, Juan Manuel Fangio took his Maserati to victory.
Twenty eight years later, also on May 19, McLaren's Alain Prost drank the champagne, while in 1996, another Frenchman - Olivier Panis - memorably won his first and only F1 race, for Ligier. -GMM